Radioative photographic articles



Patented July 15, 1952 UNITED RADIOACTIVE PHOTOGRAPHICE ARTIC ES Jack DeMent, Portland, Oreg.

No' Drawing. Application JulylO, 1948, I

Serial No. 38,157

This; invention relates to broadly novel improvements and articles ofthe photographic arts; more particularly, to radioactive photographicarticles and materials, to methods and means for the prcduction thereof,and the like. H e

It is an bjectof this inventionto make available photographic articleswhichare characterizsdasradhactive; for example, photographic materialsand emulsions which are radioactive in direct proportion to thereduction thereof. It. is also among the objects of the presentinvention to provide methods and means forthe treatment of photographicmedia, such that after productionof the latent image and its subsequentdevelopment and fixing the said image can be renderedradioactive indegree which corresponds to'the density of reduotioninsaid photographicmedia. V It is an object of this invention to provide methodsand meansfor the production of radioactive images upon a variety of surfaces, thesaid images, representing for example the chemical and/or photochemicaleffects of such agents as light, ;X-rays, radioactive radiations, heatmagnetism, chemical vapors and the like, pressure-and 34 Claims. (01.250106) mechanical energy, and the like,-as set forth in more detailhereinafter.

It is an object of the present invention to supply;the medical,dermatologic and like arts and sciences with an improved source oftherapeutic radiations; for example, a radioactive photograph source-ofgamma rays or electrons. In irradiatiorrtherapy, as is Well known, it isimportant not to involve healthy, non-malignant tissuewhich isadjacentto cancerous or other malignant tissue; presently, the methods ofirradiation are relatively ineffectual in that healthy tissue mayreceive harmful doses of say gamma rayswhen treatment is being given askin cancer of yery irregular configuration. In the present invention.for example, a suitable photograph is taken of .thediseafsed area orgrowth, which may be-beneath the skin in some instances, and thisphotograph is then made radioactive so that it in turn may; beplacedagainst the diseased area and provide an irradiation of field contourwhich corresponds exactly with the configuration of the area undertreatment, not involving adjacent and per-- .haps! healthy tissue. V Asis set forth in more detailinfra, a number of modifications ofthismethgraphic articles photographic surfaces," photographic mediaand/or materials, image bearing surfaces and/or'media, light sensitive,image-forming materials, emulsions, and the like will be; taken inthebroad, customary meanings these designations convey to those skilled inthe art; such terms will be used herein to broadly designate radiationand/or other energy respon- 'sive elements upon which an image is borneor can be produced. r V i Thus, if photographic articles, supra,.areclassified on the basis of means and energies which produce the image(latent and fixed, or, nonfiXed),-then the following are embraced, asexamples: visible light (black-and-white or color) luminescence (e. g.,arising from a coating or from fluorescent matter injected into ananimal (described infra) X-rays; gamma rays; ultraviolet light; infraredradiations; beta particles and electrons; alphaparticles; ions ofvarious energies and atomic 'and/or molecular species; meg.- netism(magnetographs); electricity (electrographs); chemical vapors, fumes,gases and the like ('e. g., the Russell effect) supersonic energy; hotbodies (called pyrophotography); pressure and mechanical energy (e. g.,so-called barophotography), and thelike.

If, on' the 'other hand, classification of photographic media, and thelike, supra, is made on a more abbreviated and customary basis, thenthere is included for example, the optical emulsions (ortho-, pan-,eto.)the infrared emulsions, theultraviolet and-X-ray emulsions (which mayinvolve double coatings) black and-white, colorblind colon nuclear, andthe like; these, in addition, may be fstil'lf, or of the cinemaivariety, also, opaque, translucent or transparent. ,If a

.further distinction is made on the basis of carriers and surfaces, thenalarge number andwide variety of rigid or flexible surfaces areincluded, for example: paper and. cardboard; plastic; wood;

- metal; fabric; ceramic and glass; and the like,

7 ,50 ,odiare possible, according to the circumstance.

as is well; known to those skilled in the art;

Whereas visible images are preferredin the presentfinvention, or, atleast images which; can be. appreciated by simple means, e. g.,luminescence, this broadly novel imprqvement'is byno .means to belimited to so-called--visible images and, as describedin more detailinfra, may include photographic media which bear a substantiallyinvisible radioactive, image, an image that 1s not to be appreciated bymethods and means other-than those responsive to, radioactiveradiations, e g., photographic emulsions,- phosphor or other luminescentsurfaoes:;(e.1 g., zinc sulfide phosphor), and, in particular,--theradiation de- (1) silver halides (e. g., bromide, iodide, chlo- I ride);(2) chromium compounds (e. g., dichromates in photomechanical processes;the wellknown bichromate system); (3) baryta processes (which includes,for example, barium halides and barium sulfate); (4) cerium and/or rareearths processes (cerium sulfate in particular);

(5) cobalt processes (involving cobalt chloride as a rule); (6) copperprocesses (usually involving copper sulfate); (7) iron processes(involving such ferric compounds as the chloride); (8) platinumprocesses; (9) platinum-iron processes (in which the iron is removed byhydrochloric acid); (10) palladiotype processes (using palladium insteadof platinum); (11) silver-iron processes (the so-called kallitypeprocess using ferric oxalate and silver nitrate) (12) platinum metalsprocesses (other than platinum and palladium, using instead of thesemetals suitable compounds of I say osmium, iridium, ruthenium, rhodium);(13) the well known salted paper processes; (14) asphaltic or bituminousprocesses (using light sensitive bitumens which are precipitated byseveral methods, well known to those skilled in the art, from asphaltumand the like, Syrian asphalt as an example containing 52 per cent lightsensitive bitumens); (15) so-called oil processes; (16) so-called carbonprocessesf; and the like. In addition, as desired, a number oi -specialand specific photographic processes are well known, and may be employedherein, one example being the so-termed "metal sulfide process in whichthe following elements can be employed: Fe,'--Ni, Co, V, W, M0, Bi, Pb,Hg, Cu and Ag. I

In practically all of the afore-listed' photographic processes and mediaproduced therewith, the exposure to light or the like (supra) results inthe production of the'latent image which upon development is convertedinto the physical image, the subsequent process of fixing and washingserving to remove photosensitive material which is'not involved in theformation of the image, latent and then physical. Whereas this isgenerally the mechanism, in a qualitative sense, that is involved, thephysicalimage may be produced directly by the light or-other'energyagent, and the subsequent treatment of fixing or. the like serve topreserve it and concurrently remove photosensitive or like materialwhich is not invo1ved,as before. Thus, in the customary silver bromidephotographic material, the light exposure produces the latent image, thedevelopment results in a'physical image of reduced silver, and

the-fixing removes extraneous silver bromide from the unreduced areasof-the material, as is well known. In many-other photographicprocessesthis general scheme is also involved.

' Briefly.- in the present invention a photographic material orthe-image borne thereupon is. rendered selectively and preferentiallyradioactive in voneor-more of several ways, as desired, and examples ofwhich" are set forth-in more ,detail hereinafter, for example: (a) bythe pro- .ductionzof radioactivity the element and/or 4 compoundcomprising the image of a developed and fixed photographic material orsurface, say in the case of a silver image by bombardment with deuterons(say from a cyclotron) or with neutrons (say from an Ra-Be or Po--Beneutron source), or other elements which comprise the image with othersuitable radiations and particles known to induce radioactivity; (b) bypartly or completely replacin'g'the silver or other image with suitablemetal toners and/or dye and dye-like toners (so-called mordants) andthen inducing radioactivity by irradiation with neutrons, deuterons,alpha particles and the like, according to the element involved and theradioactivity characteristic desired, or, by use of radioactive tonersand/or mordants to partly or completely replace the silver image, e. g.,radioactive gold, cobalt, and the like (described infra); (c) by partlyor completely pigmenting in the well known oil-processes and/orcarbon-processes with radioactive pigment or pigment subsequently maderadioactive by irradiation. 1

Therefore, the articles produced by the present methods and means,outlinedsupra, may be classed as (a) those which are susceptible toinduced radioactivity, this being produced by suitable irradiation; (11)those which are radioactive by virtue of employment of radioactivematter in treatment of the image or in the production of the image; and,finally, those which are susceptible to fission or are radioactive byvirtue of fission, e. g., uranium, thorium, lead, thallium, bismuth andlike element bearing photographic media, as described in more detail inthe examples infra. When radioactive compounds are usedin (c), supra,they may be naturally radioactive and/or artificially radioactive, asdesired.

- According to the'present invention, examples and representativeembodiments of which are set forth in the following examples, butwhichexamples and embodiments being understood as subject toconsiderable variation and'n'iodification without violating the spiritor scope of this invention, as desired, both so-called negatives andso-called positives, or any of the conventional forms thereof, e. g.,reductions and en'- largements, can be used. These, as described supra,may be on practically any kind of carrier, and such a carrier may berigid or flexible, as desired; moreover, these photographic media maycomprise one or more of the many specialty forms of photographic mediawell known to those skilled in the art, e. g., strippable photosensitivecoat- 'ings and films. When choice is madeof-negative or'positive,consideration must be-given the areas of those articles which are to berenderedradioactive. In the usual case, that of the positive 'or print,the so-termed highlights will be most lacking in radioactivity, whereasthe image and vention may be directed'to radioactive images, theseradioactive images may be positive or negative or any conventionalcombination thereof, ;as desired. Moreover, by methods well 'knowntothose skilled in the art, the present invention is tractable in certaininstances where suitable photographic media are used to reversal,wherein one part of a photo material may be radioactive and-another partmay be image bearingin'the customary sense of the word. Emample-1.--Thepresent example of this invention-comprises the most elementary andsimpleform; that is, say a silver 'bromide print (positive) or negativeis prepared in the customary manner,by production of the latent image,its development and'fixing, with especial care being taken to remove allunreduced silver or the like (other metalsfor example which may form,the-basis of photographic processes, supra) from the emulsion. In aprintthe image will correspond to reduced 01' elemental silver or the like,and vice versa in the case of the negative. The photographic material,subsequent to the production of the physical image (i. e., changing the.latent image to the physical image and removing by well knownphotographic methods and means all unreacted'substance), is thenirradiated so that induced radioactivity is produced in the reducedsilver or the. like areas,- corresponding to the image (in a positive)or just the reverse (ina negative). l a

In the present Example 1, and other examples herein where induced.radioactivity is produced by irradiation or the. like, choice of the.radiation andits source and the conditions of employment will, .as iswell known to those skilled in the. art. vary according to theelement(s) involved, the characteristics orthe radioactivity to bevproduced, and the, intensityor level of radioactivity to be imparted ina given instance of application. As a preferred source of radiation, ofneutrons in particular, the neuclear reactor (e. g., graphite pile,uranium pile, heavy water pile..and.the like) proves most convenient.The

type pile, an irradiation of from say a week to a month will produce in'a silver bearing photographic article radiosilver which has a half life'of 225 days, emitting beta particles and gamma rays; the radioactivitywill correspond to approximately 8 millicuries per gram of silver.Instead of pile-irradiation, to produce radioactivity by neutronreactions, other sources include the cyclotron and, in particular,mixtures of radium and beryllium or of polonium and berylllum. Asdesired, alpha particle-irradiation, from say radium or polonium, can beemployed to produce artificial radioactivity in the silver or the like.

Radioactive photographic articles and media of practically anyradioactivity characteristics, e., g., in the matter of the radiationemitted (e.; g., alpha rays, beta particles, gamma rays, X-rayshthehalf-life (e. g., from minutes (as in radioantimony and radiotitanium)to days (as in -radi obarium and radiobismuth), weeks or months. (as inradiosilver and radiosulfur), to years (as in radioiron) and, centuries(as in radiocarbon, radium, uranium and thorium), and the intensitydepending upon the atomic species, the. nuclear reactions produced, andtheamount of reactant (say the size of the photographic article), can beproduced by use of photographic articles and media suitably chosenxfromaconsideration of the element or elements which comprise thephotosensitive member of the system orwhich make-up the image or thehighlights. COther photographic processes than those involving silverhalides are listed hereinbefore and, for example, involve alkaline earthelements, rare earths,.and light and heavy metals, all of Which artractable to irradiation by neutrons, deuterons, alpha particles, andthe like, the consequence being radioisotopes more or lesscharacteristic of the atomic reactant. Variation of the photoreactantmay be made as desired, and any such variation will not be construed asviolating the present invention.

Example 2.'Ihe present example is like Example 1, supra, in that thephotographic article is prepared as before, but is characterized asfissionable; that is, the induced radioactivity arises from the processof atomic fission, and the isotopic debris and the like may be said toaccount for the resulting radioactivity. According to the present formhereof the photographic article is prepared by a photographic process,examples of which are given supra, which results in an image(orhighlights or the like, as explained hereinbefore) comprising afissionable element. As examples of fissionable elements, in addition tothose of atomic numbers above and including transuranium elements, theelements covering the range of atomic numbers 83 (bismuth) to 73(tantalum) "are included.

These elements (numbers 83 to '73) respond by spallation to suchprojectiles as alpha particles, deuterons and neutrons of energies up to400, 200, and m. e. v., respectively. Such radiations are preferred asoriginating in a frequency modulated cyclotron, e. g., the 184-inchBerkeley cyclotron,'or other convenient and well known sources. In thecase of platinum, alpha particles of say 400 m. e. v. (million-electronvolts) pro duce spallation and'this is especially desirable in the caseof platinum prints, platinotyes and like photographic articles; In thecase of thallium, both deuterons and alpha particles are effective. Thespallation reaction of theselighter elements with high energyparticles'obtained-in the cyclotron differs in some important respectsfrom that resulting from the fission of such elements as uranium,thorium, plutonium, protoactinium and the like, when slow or fastneutrons are employed. There is, for example, the absence of a chainreaction that characterizes high energy fission, but the yield is highand a more even split is produced in spallation.

Example 3.-In contrast to theprevious Examples 1 and 2, wherein aphysical image is produced in a photographic article and then bysuitable methods and means rendered radioactive, generally withoutgreatly altering the physical image in the usual sense, the presentExamples 3 and 4, for example, rely upon modification of the physicalimage; e. g., partial or complete replacement or chemical alteration ofthe say reduced silver, as an example, whichmay be said to comprise thephysical image.

Briefly, the presentexample, as well as others of a like nature, may besaid to embrace radioactive toning," the purely photographic or chemicalprocess, as "contrasted to staining, wherein the image of a photographicarticle is partlyor fully replaced or modified by said (a) certainradioactive compounds and/or (b) certain substances which by suitableirradiation (of. Examples 1 and 2) are rendered radioactive in thedesired quality and quantity. In the silver bromide print, for example,toning is directed to changing the nature of the reduced silver and, asis well known, this general method-of changing the color of aphotographic article,

may be directed to inorganic salt replacement of the silver, orchemically changing, the silver (for example) so that itcan be mordantedor at least in ,a chemical sensewith basic dyestuffs or, in general forpresent purposes, basic compounds usually of an organic character.Radioactive toning may or may not result in distinctive and/or desirablecolor changes in the photographic article and, as desired, radioactivetoning and radioactive mordanting may cause not the silghtest color orphysical change, at least insofar as appearance to the eyeis concerned.

The methods of toning are well known to those skilled in the art, andvary accordingto the toning agent and the photographic material, sodetailed instruction as to employment is not deemed necessary in thepresent specification. A large number and wide variety of toning agents,compounds-and formulations are known, and examples are as follows: (1)ammonium molybdosulfide; (2) ammonium carbonate; (3) sodium tetraborate;(4) auric chloride; (5 sodium aurochloride; (6) vanadium chloride; ('7)uranyl chloride;:(8) gold-platinum mixtures; (9,) lead salts such as theacetate or the nitrate; (10) potassium chlor platinate; (11) selenium;(12) sodium polysulfides and the like; (13) sodiumthioantimonate; (14)sodium tungstate; (l5 cobalt salts such as the chloride; (16) copper(ic)salts such as the sulfate; and the like, one or more of which toners maybe used in com: bination, as desired. a a

In the present Example 3, the photographic article is toned, by methodswell known to those skilled in the art, with material which isradioactive, the-radioactive ingredient finally appearing as part or allof the image or the like of the photo article under toning. In the caseof alkaline earth element toners, e. g., Ba, Mg, Ca, Sr, I prefer toreplace part of the alkaline earth element with the alkaline earthelement radium, in compound form corresponding to the nonradioactiveanalog(s). The radioactivity of the toned article will then depend uponthe quantity of radium which has been taken up in the toning process,and this may range from levels of micrograms, through milligrams, tomultigrams; the microgram level is useful in research and tracerstudies, for example; the milligram level in therapy and photocopying(using a master copy of the radioactive photographand placing in contacttherewith prints or negatives or the like to be reproduced) and, themultigram level for special applications of industrial radiography. Theradium is conveniently a double salt of say barium. I

Otherwise, it is preferred to use artificially radioactive elements, 1.e., radiois'otopes, in the toning process. Radiocobalt-GO may beused-for the non-active cobalt; radioantimony (122 and 124) for theusual antimony in thioantimonates; radiocopper64 for non-active copper;radiogold (especially Au -199) for non-active gold in the conventionalgold toners; radioiron (say and/or59) for ordinaryiron; radiomercury inmercury toners; radioselenium-75; and radiotungsten (say 185 and/or I37)These radioisotopes can be produced in a variety of reactions, but it ispreferred that they be formed by pileirradiation. As desired, theradioisotope can be introduced into the toning compositions or S0111?tions, or, the same if not too complex, can be exposed to neutrons withthe production of the radiotoner, .thus eliminating the necessity ofchemical operations with dangerous radioactive matter. p

, Example 4.-The present Example 4 is related to Example 3, supra, inthat photographic articles are toned with the metal or inorganic or liketoner, chosen from a consideration of" its qualities to acquireradioactivity, e. g., theele merits listed under Example 3, and, finallyrendered radioactive by suitable irradiation, e. g., pile derivedneutrons, or the production of a nuclear reaction with deuterons, alphaparticles or the like, effective to form a radioisotope which may or maynot be the atomic species initially used. Examples 1 and 2 set forthmeans for the production of artificial radioactivity which are to beapplied in the present example.

Moreover, elements susceptible to fission, for example those set forthin Example 2 are to be included in the present example and embodimenthereof. Thus, the conventional uranium toners of the photographic artare applied in the customary manner to the photographic article and thenexposed to neutrons so as to produce fission, with the consequence ofliberation of radioactive fission products therein photographic article..As desired, the ordinary uranium or enriched'(with U-325) may beemployed. In specific and special instances of application of thepresent invention, relatively pure or pure uranium-235 isotope may beused, which isotope is responsive to thermal neutrons, as is well known.However, it is anticipated that the need for this improvement or formhereof will be very slight, and restrictedto research.

It is in this connectio that in any or all of the present exampleshereof improvement wherein nuclear reactions provide the radioactivitythe reactant may, as desired, be in pure isotopic form or in materialenriched in a given isotope, so chosen because it exhibits special anddesirable properties well known to those skilled in the art.

Example 5.The present Examples 5 and 6 correspond to the previousExamples 3 and 4111 that radioactive toning processes are employed, or,toning processing susceptible to induced radioactivity by sayirradiation or fissioning are involved. In the present embodiment saythe silver image is chemically altered, e. g., to brown silver sulfideor silver ferrocyanide or the like, and subsequently, at option,mordanted with basic substance such as a dyestuff. Furthermore, asdesired, the radioactive toner or ingredient may comprise the materialsuch as sulfide which changes the metal image and/or the mordantingsubstance, the basic material corresponding to the basic dye in theusual method.

Thus, taking silver halide photographic media as examples the reducedsilver of the image or the like is chemically altered so as to form acompound such as silver ferrocyanide, silver sulfide or the like,and'this in turn can be used as the mordant for basic dyes and chemicalcompounds. In one embodiment hereof, the use of the basic dye or thelike is optional, since the production of a silver or like derivativemay serve satisfactorily. Thus, in for example the so-called liver ofsulfur toning bath, e. g., 60 grains of potassium polysulfides (liver ofsulfur) in say 10-15 ounces of hot water, with 1 drop of ammoniumhydroxide for each 4 ounces of the mixture, part or all of the sulfurmay be replaced by radiosulfur-35 (the radioisotope made, say, by. thepile-irradiation of sulfur) and/or radiopotassiumiz (prepared'in thesame way).

The prints or other like articles are merely immersed in thisradioactive toning composition until thedesired level of activity has.been impartedv to the product. Likewise; in:the,gold toners; of which anumber of formulations are well known and not novel with me, radiogoldmay. be substituted for the usual gold, in part or completely; with orwithout other elements," e; g., sulfur, being radioactive. 1 In yetanother version hereof example, the photographic article is converted,say by the afore-described.procedure, and is then dyed with a basicdyestufi? containing one or more species of radioisotope. As examples'ofbasic dyes, which list is not by far exhaustive, there is includedsafranine A; auramine; methylene blue; methyl violetyVictoria green; andchrysoidine'3R; and th'elike. It is not anticipated that this particularembodiment will be useful for other than research and specialtyapplications of the present invention, but accordingly the basicdyestuffs or the like (which may or may not be colored) serve as meansfor the introduction of radiocarbon-'14 into the photographic medium, inlarge amounts in view of the number of carbon atoms which makeup suchcompounds. The radiocarbon-14 is preferably derived from neutronirradiation in the graphite pile, and the radioactive basic substance issynthesized previous to employment in the mordanting process by methodsand means well known to those skilled in the chemical art.

Example (is-This embodiment is like that set forth in Example 5, exceptthat the photographic material is changed to a mordant Or mordantableform,'with the optional employment of basic dyes or the like, supra, andis then rendered radioactive by (a) nuclear reaction and/or (b) byproduction of fission with the consequence of radioactive debris andfission products being deposited. The methods for producingradioactivity by either of these agencies are set forth in more detailhereinbefore. For the radioactivity that results from fission byneutrons, the uranium toners are used, and the uranium in suchformulations may, as desired, be enriched in uranium-235 isotope.Example 7.The present embodiment hereof comprises somewhat of adeparture from previous examples and is based on what are known aspigment processes, a variety of which are known; for example, theoilprocess, the bromoil process, the dichromate or gum dichromateprocess, and the like, including. the so-calle'd carbon process. Forpurposes of the present specification and disclosure, a representativeprocess (pigment process),-the bromoilmethod is hereinafter-set forth;as desired, variations and -modifications hereof will be taken toinclude other species of the general category of pigment processeswithout violating the spirit and scope of the present invention.

The present Examples '7 and 8 correspond to pigment processes in which(a) radioactive pigments are used and/or (1)) radioactivity is producedsubsequently by say irradiation or fission, as described supra.

Thebromoil process is based on the principle that a gelatin or likecoated member, e. g., paper, wood, glass,'accepts or repels oleaginousmatter, e. g., greasy ink, in proportion to the amount of water presentin the article. For example, an ordinary bromide print is made andbleached out so that the visible image of the regular printdisappearing, ;leaves. an image in gelatin. The bleached bromide printis soaked with water and blotted off. Radioactive oil pigment, or, asdescribed in Example 8, radioactively susceptible oil pigment, isapplied via a brush and where parts of-the article holda large amount ofwater,-as in the highlight areas, the ink or oleaginous matter isrepelled. The deeper tones and shadows hold progressively lesser amountsof water, and therefore accept the oily matter, e. g., theink, inproportion to-the exact quantities. Much control can beexercised, andmodifications of the amount taken up are readily possible. Such aproduct is as permanent as an oil painting, since the silver or otherimageor the like is actually replaced with one of pigment and oil.Amidol is generally the best developer, anda number of formulas as wellknown." Furthermore, bromoil transfers can be made, resulting inradioactive duplicates; this is done from a freshly inked printtoanother paper or like support. placing thetwo in contact by means of.a press.

As examples of radioactive pigments which-are used in the present formhereof, there is included: radiobarium-131, which when pile producedusually contains radiocesium- -l3l (for bariumwhite, used in makinginvisible images) radiocalcium- (forgypsum or. satinite) radiozinc-69(for China White or.zinc;white)-; radioantimony (for 'fantimony white)radiotitanium-51 (for titanium white) ;radiobismuth-21O (for bismuthwhite); .radioiron-55 (for sienna, ochre) radiochromium51 (for chromeyellow and the like); radiocadmium- -(for cadmium yellow) radiocobalt-GO(for-cobalt yellow); radiomercury (for cinnabar red) radiocopper-64 (forBremen Blue) radiomanganese (for ,manganese black) radiocarbon-l4 (forcarbon black); and the like. These radiopigments are preferably producedby pile-irradiationf'but, as desired, may be derived from other sourcesand nuclear reactions. Those elementsor pigments which are fissionable,as set forth supra, are employedlikewise. Example 8.-Instead of.introducing radioactive matter in the pigment process, as set forthsupra, the photographic article is prepared witharadioactivelysusceptible or fissionable pigment or materiaL'and is then renderedradioactive by suitable treatment, e. g., pile-irradiation, exposure toalpha particles, deuterons or the like, as explained hereinbefore. As inExample 7, the pigments set forth are employed and then. thearticlesubjected to radioactivity inducement agency; furthermore, aside fromthepigments listed under Example fis'sionable pigments include uraniumdioxide (uranium. brown); uranium black or green (U308) uranium red(uranium trioxide) uranitum .yellow (sodium. uranate) uraniumprange(potassium uranate); also, complex compounds involving neutron or.deuteron susceptible ele-: ments such as zinc, copper, andcobalt.Moreover, instead of uranium as the fissionable pigmentf. lighterelements, say as oxides or silicates, can beemployed in suitablecomminuted forms in the customary oil or greasy vehicle, as well asheavier fissionable'elements such as thorium dioxide and thoriumsilicate; in addition, compounds having more than one fissionableelement may be employed, e. g., thorium platinocyanide, thorium uranate,and thelike.

According to Examples 1 to 8, the radioactive photographic media willexhibit radioactivity characteristics. which in part will depend uponthe method'and means of production. Thus, the method wherein r'adiactivereactants, mordants, dyesv andcompounds of say a basic nature, andpigments and the like, are introduced into the photographic media in aradioactive form will result in a product which does not exhibitextranef ous'radioactivities, e. g., radioactivities in other elementsand materials making up the photographic article such as carbon. Hence,the image, highlights, or the like, will be more purely radioactive thanthose products wherein photographic media are irradiated-by sayneutrons, with the production of secondary and extraneousradio'activities; in the case of this invention where fiissioningisresponsible for radioactivity, then there will be 'a multitudeof'radioactivities, corresponding to the plurality-of radioisotopes andfission products.- Therefore, choice of a given method, form, article orembodiment must be made out of consideration of the, utilizationdesired;

Whereas the terms and expressions image, physical image, highlight(s),latent image and the like are used in their customary physical andphotographic meanings herein, it is seen thatfthepresent improvement hasasits consequests the radioactive, image, radioactive physical image,"radioactive high1ight(s), and thelika'jwhich are to be construedasembracing any' sort of images orrepresentations in gradientlyradioactive areas upon or of a photographic medi- 'um, visible orinvisible to the ey'e, detectable or substantially non-detectable byother chemical and/orphysical methods and means of appraisal,

or the like. Hence, a radioactive image may range from simple andcomplete reductions and non-reductions to any and all degrees andgradations thereof. The nature, characteristics, choice and mode ofproduction of the image will depend upon the application desired, andthis in turn mayrange from simple geometric .fig.ures,. dots and} lines,to radioactively black-and-white images, to more complexim ages such asmay be represented by numerals, letters, reading matter and printedmatter and the like. In short, the

. term"image" and the like is herein equated with intelligence and itsconveyance. l

According to the present invention, a variety of refinements,embodiments and structural and geometric forms and modifications can beproduced'. Thus, a combination of radioactivities in a given image orintelligence conveyance can be produced, e. g., alpha emitters in thepresence of neutron-reactive -elem'ents, e. g., gadolinium, lithium,boron, cadmium,- which neutron reactive elements in -turn emit specialradiations, e.' g., 'soft-"electrons; or, the radioactive image maybecarried on a member of nuclear reactive metal, su ra; or otherdesirable-material, say contain ing radiation sensitive chemicalcompounds, e; g.,

phenylenediamine (which turns blue in the presence of short wavelengthultraviolet light); or, the radioactive image may be covered withrespons'ive films or coatings'including sputtered or evaporated (vacuumfor example) metals and/ or compounds, e. g., those supra, alsoiiuorides(with the consequence of hiding of any visible image that may exist) aswell as luminescent'solids such as zinc-'o-silicate, zinc sulfide,calcium tungstate, and like phosphors; or, covered with strippable filmsor rigidly carried photosensitive emulsion; or, living matter such asbacterial culture media, diseased skin or other tissue; or, ultravioletemittingis'olids such as calcium tungstate to act as intensifyingscreens in photographic applications; and the like, s'uch'modificationsand variations needing no further description herein. Moreover, theradioactive image may be employed in specialized photocopying andphotoduplicating processes by -m'erely placing .photographic material incon- 1'2 tact with the radioactive image and allowingTsame to remain fora suitable exposure, developing and fixing according to the art; inthisphase, a stack or plurality of photographic papers orfilms, for example,may be used when the radioactive image emits gamma rays. i

This invention is, inaddition', not limited by geometric considerations;that is, while it is anticipated that plane surfaces will bc'of'm'ostgeneral utility, involving say one dimension, multidimensional forms andgeometries of'any kind are not to be excluded. This is taken to includenot only surface coatings and films, which'in turn may be of more thanone dimension "and geometry, but also.solid geometries and .t'hreedimensional radioactive images andradio'active: ly photographicarticles. image(s) may comprise part or all of a cylinder or a' sphere,for example, or say bodies 'corre sponding to crystals of any kind,thesolid mass thereof comprising three-dimensional or stereographic-like radioactive articles. In the'matter of variations ingeometry, the simplest may be represented by pictures and fiatphotographs, the more advanced by cameo and intaglio'surfaces (which mayor may not be plane, cf. supra) and the most advanced by analogs ofstatues-and solid representations of this nature.

Furthermore, any of the specialty physicochemical treatments, processingand the" like known in the'photographic' and related arts may bedirected to the present invention; thus, the radioactive image may berigidly'fixe'd' on or within ceramic carriers; or, extraneous'o'rganicmatter may be pyrolized or burned out, eluted out by solvents, changedby chemical reaction; or',the like, as'desired.

Iclaim:

1'. The method of irradiating an object with radioactive radiationswhich comprises the steps of taking a photographic image of the saidobject,'causi'ng the said image to' become radio active by treating samewith radioactive material, and applying the thus treated image to thesaid object.

2. The method of irradiating an object with radioactive radiations whichcomprises the steps of taking a negative photographic imageof'the saidobject, the said image being approximately the real size of theobjectjcausing the said nega* tive image to become radioactive bytreating same with radioactive material, and applying the thus treatedimage to the said object.

3. The method of irradiating an object as set forth in claim 1 whereinthe said radioactive material emits gamma radiation.

4-. The method of irradiating an object as set forth in claim 1 whereinthe said radioactive material emits beta radiation. a

5. The method of irradiating an object as 'set forth in claim 1 whereinthe said radioactive material emits alpha radiation.

6. The method of irradiating an object as set forth in claim 1 whereinthe said radioactive material emits neutron radiation.

'7. A radioactive structure which comprises a pho'toim'age membercontaining radioactive matter having a half-life of betweenapproximatelyone minute and 2 X 10 years, the quantity of radioactive matter in thesaid photoimage niemQ her being in direct proportion to the reducedareas of the photoimage member, said radio'- active photoimage memberbeing carried upon non-radioactive support means.

8. The radioactive structure set forth in claim Thus, the radioactive 47 wherein the said radioactive matter emits gamma radiation.

9. The radioactive structure set forth in claim 7 wherein the saidradioactive matter emits beta radiation.

10. The radioactive structure set forth in claim '7 wherein the saidradioactive matter emits alpha radiation.

11. The radioactive structure set forth in claim '7 wherein the saidradioactive matter emits neutron radiation.

12. In the process of preparing a photographic image including the stepsof formin a latent image upon a photographic article and processing thesaid latent image into a physical image, the improvement of impartingradioactivity to the said physical image in direct proportion to thereduced areas of the said image, said radioactivity characterized ashaving a half-life of between approximately one minute and 2 X 10 years,whereby a radioactive photographic image is produced.

13. In the process set forth in claim 12 wherein the said radioactivityis gamma radiation.

14. In the process set forth in claim 12 wherein the said radioactivityis beta radiation.

15. In the process set forth in claim 12 wherein the said radioactivityis alpha radiation.

16. In the process set forth in claim 12 wherein the said radioactivityis neutron radiation.

17. The method of irradiating an object as set forth in claim 1 wherein.the said radioactive material emits gamma radiation.

18. The method of irradiating an object as se forth in claim 1 whereinthe said radioactive material emits beta radiation.

19. The method of irradiating an object as set forth in claim 1 whereinthe said radioactive material emits alpha radiation.

20. The method of irradiating an object as set forth in claim 1 whereinthe said radioactive material emits neutron radiation.

21. As a new article of manufacture, a source of radioactive radiationcomprising the combination of a non-radioactive supporting member and anelement bearing a photographic image carried upon the said member, saidphotographic image containing radioactive matter of half-life betweenapproximately one minute and 2 X 10 years, the amount of radioactivematter in the said image being in direct proportion to the reductionthereof.

22. The article set forth in claim 21 wherein the said radioactivematter emits gamma radiation.

23. The article set forth in claim 21 wherein the said radioactivematter emits beta radiation.

24. The article set forth in claim 21 wherein the said radioactivematter emits alpha radiation.

25. The article set forth in claim 21 wherein the said radioactivematter emits neutron radiation.

26. As a new article of manufacture, a source of radioactive radiationcomprising the combination of a non-radioactive supporting member and anelement bearing a photographic image carried upon the said member, saidphotographic image containing radioactive matter having a half-life ofbetween approximately one minute and 2x 10*" years, the amount ofradioactive matter in the said photographic image being in proportion tothe reduction thereof.

27. The article set forth in claim 26 wherein 14 the amount of the saidradioactive matter in the said photographic image is in directproportion to the reduction thereof.

28. The article set forth in claim 26 wherein the amount of the saidradioactive matter in the said photographic image is in inverseproportion to the reduction thereof.

29. In the process of preparing a photographic image including the stepsof forming a latent image upon a photographic article and processing thesaid latent image into a physical image, the improvement of causing thesaid physical image to become radioactive in proportion to the reductionthereof, said radioactivity having a halflife of between approximatelyone minute and 2X10 years, whereby a photographic source of radioactiveradiation is produced.

30. In the process set forth in claim 29 wherein the said physical imageis radioactive in direct proportion to the reduction thereof.

31. In the process set forth in claim 29 wherein the said physical imageis radioactive in inverse proportion to the reduction thereof.

32. A radioactive structure which comprises a photoimage membercontaining radioactive matter having a half-life of betweenapproximately one minute and 2 l0 years, the quantity of radioactivematter in the said photoimage member being in proportion to the reducedareas of the photoimage member, said radioactive photoimage member beingoarried upon non-radioactive support means.

33. The radioactive structure set forth in claim 32 wherein the quantityof the said radioactive matter in the said photoimage member is indirect proportion to the reduction thereof.

34. The radioactive structure set forth in claim 32 wherein the quantityof the said radioactive matter in the said photoimage member is ininverse proportion to the reduction thereof.

JACK DE MENT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 821,655 Lieber May 29, 19061,406,488 Pugh Feb. 14, 1932 1,882,426 Kalix Oct. 11, 1932 2,206,634Fermi et al. July 2, 1940 FOREIGN PATENTS Number Country Date 5,182Great Britain of 1912 OTHER REFERENCES 1 Wall: "Intensification andReduction, pp.

15-18, American Photographic Publishing 00., 1927. CopyinDiv. 67.

Ellis et al.: Artificial Radioactivity, Proc. Royal Soc. (London), vol.146, pp. 206-7 (1934). Copy in Patent Office Library.

Towler: The Silver Sunbeam, published in N. Y. (1864) by J. H. Ladd,pages 272-273. Copy in Scientific Library.

Saint-Victor: Comptes Rendus, January-June 1858, tome 46, pages 448-452.Copy in Sci. Library.

Ser. No. 395,760, Schopper et al. (A. P. 0.), published May 11. 1943.

